Field
Aspects of the present invention generally relate to power control of an image forming apparatus.
Description of the Related Art
In recent years, with increasing demands for power saving and environmental awareness with respect to an image forming apparatus such as a multifunction peripheral (MFP), it has been necessary to provide a power control method capable of shifting the image forming apparatus to a sleep state (power saving state) as often as possible in order to reduce the standby power.
Japanese Patent Application Laid-Open No. 2007-296723 discusses an apparatus which returns from a sleep state by outputting an individual interrupt signal for each return factor which occurs at an input-output (I/O) controller. According to the configuration discussed in Japanese Patent Application Laid-Open No. 2007-296723, the individual interrupt signal is transmitted to the main controller for each return factor.
On the other hand, it is necessary to maintain operability of the MFP while realizing a comfortable operation environment which does not cause a user to notice that the MFP has returned from the sleep state, where possible. However, in a case where the MFP returns from the sleep state in response to a return factor from a main unit of the MFP, the number of signals transmitted via an interface (I/F) is increased if an individual interrupt signal is returned to the controller for each return factor according to the conventional technique. Therefore, it is necessary to perform control so that the controller and the main unit of the MFP can share the return factor while minimizing the number of signals transmitted via the I/F.